Angola’s president João Lourenço has dismissed Africa’s richest woman, Isabel dos Santos, as head of the country’s state oil company, in a bold move to wrest power from the family of the country’s former leader. The daughter of former president José Eduardo dos Santos, who stepped down ahead of elections in August after 38 years in power, had run Sonangol for just under 18 months, having been appointed by presidential decree in June 2016. The move to replace her with the secretary of state for oil, former Sonangol executive Carlos Saturnino, underscores Mr Lourenço’s apparent determination to move swiftly against the old regime and to establish his own power base.

Until now, a series of moves against allies of the former president had been variously interpreted as the first signs of something bigger or choreographed theatre cooked up with Mr dos Santos, who is still head of the ruling Popular Movement for the Liberation of Angola (MPLA), to give the perception of change. But the move to replace Ms dos Santos, alongside six other Sonangol board members, is the first direct assault on the patronage of the Dos Santos family, taking control of an energy industry that has been the primary source of Angola’s wealth since the end of its brutal three decade-long civil war in 2002.

“This is the big one,” said Ricardo Soares de Oliveira, an Angola specialist at Oxford university. “It’s no longer cosmetic changes.” Since taking office in September Mr Lourenço has replaced the head of the central bank, Angola’s government-backed diamond company and the boards of all three state-run media companies.